Abstract Detail

Conservation Biology

Reichenbacher, Frank [1].

A New Monitoring Method for Listed Endangered or Threatened Plant Species.

Implementation of Endangered Species Act (ESA) goals and objectives can easily lose coherence due to the differing species monitoring methods and practices adopted by federal, state, and local agencies, tribal governments, and private landowners. This problem is illustrated by the federally endangered desert shrub Purshia subintegra (Rosaceae; Arizona cliffrose) which occurs in four discrete substrate-specific locations in Arizona. These four locations are administered by Bureau of Land Management, Coconino and Tonto National Forests, and the San Carlos Indian Tribe.
The monitoring that has been done has suffered by the tendency to try to do too much and then falling short of what is needed to achieve the minimum requirement, which is to ensure the species does not go extinct. Monitoring populations of P. subintegra began in the 1980s and 1990s, even before the species was listed, with energetic expenditures of staff time and agency resources. The effort could not be sustained, and more to the point, much of it was not necessary.
With funding from the U.S. Fish and Wildlife Service via the Endangered Species Act Sec. 6 funding mechanism I developed a method of monitoring using the Point-Centered Quarter Method to sample randomly scattered points in P. subintegra habitat.
Initiating the program for any one species might require several mandays commitment in order to derive prior estimates of distribution and density, but once initiated, my approach will require only a 3-4 manday field commitment and 1-2 mandays to analyze data at each site that should be capable of detecting a 10-20% decline in population with 95% confidence. It requires only a GIS application, a hand-held GPS unit, a compass, and a laser range finder to gather data and the R for Statistics and a spreadsheet application to analyze it.
I am preparing to submit final products to USFWS including detailed protocol and GIS procedures in the ESRI and Quantum GIS platforms and R scripts for each involved agency.
I propose that the most efficient monitoring program for long-lived, infrequently recruiting species such as P. subintegra (includes most desert perennials) should follow this prescription:
Before the actual monitoring begins, prior data are needed to identify areas of high concentrations of individuals and derive population density estimates.
Try to devise a monitoring plan that does not require permanently marked plots or transects.
Consider a plotless distance sampling method.
Focus on the larger adult plants in the population. They are likely to be more important to population viability than hard to document recruitment (which is likely highly episodic in nature and easily missed with a monitoring effort that engages only once every few years).
Do not attempt to mark individual plants. For most plants markings are ephemeral and, in some cases, the markers themselves may even be toxic to the plant.
Leave demography to your academic/citizen science partnerships, though it is important that monitoring be informed by the results of demographic modeling.

1 - University Of Arizona, Desert Laboratory On Tumamoca Hill, 8657 E. CLYDESDALE TR., SCOTTSDALE, AZ, 85258, United States

Purshia subintegra
rare plants
population biology
population decline
limestone endemic
monitoring study
species conservation
endangered species
threatened species.

Presentation Type: Oral Paper
Number: CB3003
Abstract ID:24
Candidate for Awards:None

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